This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. This collaborative project involves the proteomic characterization of signaling complexes in neuronal cell axoplasm. Two types of complexes are under investigation, those important for long distance communication along the axon, and those involved in localized responses. Both affinity and differential proteomics incorporating quantitative mass spectrometry methods are being employed. In addition, mass spectrometric methods are being developed to identify and establish novel posttranslational modifications in neuronal axoplasm proteins.